My girlfriend and I had protected sex while she was on her period and the condom was pulled all the way to my head but not off and I hadn't cum yet. Then the next day or the day after that she was off her period. Two days later she spotted reddish brown a

Condom Use. A condom that is partially removed during intercourse may or may not cause spillage of semen. There is a significant amount of semen released prior to ejaculation. It is unlikely that this was a significant release based upon your discription.
Rest of the story? Is there more to this? If you are asking if she can be pregnant, it is unlikely, mostly because if she was bleeding the day you had intercourse, she could not be ovulating.